Menu Planning Challenge...Impressive, yet Kid-Friendly Dessert!

This weekend I'll be visiting the fam. As has become the custom, I'll cook lunch on Sunday for three adults and four children, ages 6-17, who are somewhat picky eaters. On the menu are fancy grilled chicken burgers with all the fixings, roasted yam fries (some russet fries for the pickies) and a veggie/salad.

My challenge is a tasty, not-too-calorie-laden dessert that will wow the adults and satisfy the kids' palate, that also matches the "Burgers and Fries" theme. Any ideas?